"You've won the lottery," said billionaire Todd Wagner. "There's no other way to really describe it. You can walk in a store and instead of saying, 'How much is that suit?' you can buy all the suits."

Wagner co-founded internet start-up Broadcast.com with Mark Cuban and sold it to Yahoo for $5.7 billion in 1999.

"The first year, of course, you're happy every day," he said.

Wagner, who grew up in the blue-collar town of Gary, Indiana, worked at a law firm before becoming an internet entrepreneur. When they were first building the business, he said, he had a negative net worth.

Reuters

(L to R) Tim Koogle, chairman and CEO of Yahoo! Inc., Todd Wagner, CEO and vice chairman of broadcast.com inc., Mark Cuban, president and chairman of broadcast.com inc., and Jeff Mallett, president and COO of Yahoo! Inc. celebrate Yahoo!'s announced acquisition of broadcast.com on April 1 at Yahoo! headquarters in Santa Clara.

"I'd put all my money into Broadcast.com — all my savings, all my 401(k). I had gotten a line of credit before I quit the law firm because I knew once I quit I'd never get a line of credit. I put all that in," Wagner said in an interview with CNBC at the Iconic conference in Boston last week.

"So I went from somebody that had zero net worth to being on the Forbes list in six years."

While that kind of money changes your life, it doesn't change who you are, Wagner said. "Wealth just amplifies who you are."

Getty Images

Entertainment execs Todd Wagner (L) and Mark Cuban pose at the after-party for Lions Gate's 'Godsend' at the Hollywood Roosevelt Hotel on April 22, 2004 in Los Angeles, California.

For him, coming into extreme wealth with the sale of Broadcast.com was like "catching lightning in a bottle," and he has since focused on giving back.

Wagner's namesake foundation, The Todd Wagner Foundation, supports a half dozen programs designed to give back to at-risk youth, from teaching technological skills to providing after school programming. He's also CEO and founder of The Charity Network, which is using technology to modernize fundraising, and has so far raised more than $200 million for charities.

Disclosure: CNBC owns the exclusive off-network cable rights to "Shark Tank," which features Mark Cuban as a judge.